An FF (i.e., Front-engine and Front-drive) car and an RR (i.e., Rear-engine and Rear-drive) car are known as the vehicle in which the power train including an engine, a coupling such as a clutch or a torque converter, a transmission for setting a gear stage and a differential for differentiating the left and right front wheels is entirely mounted in a limited space such as an engine room. Various influences may be exerted upon the characteristics of the vehicle by how to arrange the power train.
In the invention disclosed in JP-A-2-231228, for example, the engine, the transmission and the differential are sequentially arranged with deviations from the front to the back of the vehicle, and the engine is inclined backward. With this structure, the center of gravity of the power train is set at the rear side so that the load distribution to the front wheels is lightened. Moreover, the vehicule body can be lowered to improve aerodynamic characteristics. Still moreover, the engine is positioned in the foremost portion and inclined backward to raise another advantage that the compartment space is not reduced.
Incidentally, the front or rear portion of the vehicle body is the portion which performs an important function to crush at the time of a collision thereby to absorb the collision energy. In the invention, as disclosed in the aforementioned publication, the large length of the power train, as taken in the longitudinal direction of the vehicle, makes it difficult to retain the crush stroke for the collision unless the engine room is enlarged in the longitudinal direction. As a result, the overall length of the vehicle body may possibly be increased to enlarge the size of the vehicle.
In the aforementioned structure of the prior art, the transmission and the engine are arrayed sequentially at the front side of the vehicle body with respect to the axis of the differential which is arranged in the vicinity of the center axis of the front wheels. This arrangement positions the engine with a large forward deviation with respect to the center axis of the front wheels. On the other hand, lower arms supporting the front wheels are connected to suspension members at their two front and rear portions near the center axis of the front wheels so that their rear end portions are positioned at the back of the rear end position of the differential forming part of the power train.
These power train and lower arms are highly rigid members and will not crush basically at the time of a front collision so that they hardly absorb the energy of the front collision. The length excepting those longitudinal dimensions provides the crush stroke. In the aforementioned structure of the prior art, therefore, the dimension from the leading end portion of the engine to the rear end portions of the lower arms is left as the dead length which cannot absorb the energy of the front collision. The crush stroke for the vehicle body to crush has to be retained in addition to that dead length so that the length required of the engine room is enlarged. This raises a disadvantage that the overall length of the vehicle body is increased.
A main object of the present invention is to provide a power train arrangement structure capable of decreasing the overall length of a vehicle while retaining the crush stroke.